refactor: consolidate breadcrumbs to single TopBar instance

Remove duplicate in-page breadcrumbs (ExchangeDetail, AgentHealth scope
trail) and improve the global TopBar breadcrumb with semantic labels and
a context-based override for pages with richer navigation data.

- Add BreadcrumbProvider from design system v0.1.12
- LayoutShell: label map prettifies URL segments (apps→Applications, etc.)
- ExchangeDetail: uses useBreadcrumb() to set semantic trail via context
- AgentHealth: remove scope trail, keep live-count badge standalone

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/package.json

@@ -14,7 +14,7 @@
     "generate-api:live": "curl -s http://localhost:8081/api/v1/api-docs -o src/api/openapi.json && openapi-typescript src/api/openapi.json -o src/api/schema.d.ts"
   },
   "dependencies": {
-    "@cameleer/design-system": "^0.1.11",
+    "@cameleer/design-system": "^0.1.12",
     "@tanstack/react-query": "^5.90.21",
     "openapi-fetch": "^0.17.0",
     "react": "^19.2.4",